Chlorophosphonates: inexpensive precursors for stereodefined chloro-substituted olefins and unsymmetrical disubstituted acetylenes

New chlorophosphonates bearing a 1,3,2-dioxaphosphorinane ring which are useful for the stereospecific synthesis of 5-chlorofurfuryl substituted olefins and chloro-substituted dienes have been obtained by an easy, inexpensive route. The utility of some of these in the synthesis of ferrocenyl- and anthracenyl-substituted unsymmetrical acetylenes has been explored. The structures of the phosphonates (OCH(2)CMe(2)CH(2)O)P(O)CH(2)(C(4)H(2)ClO) (4) and (OCH(2)CMe(2)CH(2)O)P(O)(CH=CHCH(Cl)Ph (7) have been determined; in addition, the stereochemistry of (5-chlorofurfuryl)CH=CH(4-ClC(6)H(4)) (13b) and 2, 4-Cl(2)C(6)H(3)-CH=CH-CH=C(Ph)Cl (14a) is unambiguously proved by the X-ray structure determination.